Texman, ANYTHING can be done if you put some inginuity and time into it. If I were contemplating this swap, I would look into adapting the back of the early trans casting to the later trans and shortening and resplining the tailshaft.
I am no fan of VCCA but decades ago when they were still focused on technical issues, their magazine G & D had an article on how to adapt 50's era 3-speed gears into '37 and up 3-speed trans cases. That would be way easier than making an open drive trans case work with a torque tube. As I recall it was a simple gear swap except for shortening the later tailshaft, resplining the cut end to match the U-joint and drilling and tapping the back of the tailshaft for the bolt that retains the U-joint.
In the 50's and 60's street rodders adapted Cad-LaSalle open drive transmissions to Ford torque tube driveshafts all the time. I did the same thing with a '37 Buick Roadmaster trans but that was even easier because it was already set up from the factory for closed drive. The Ford U-joint even fit the Buick tailshaft splines!!
Anything can be done. You can do it!
